Battery chargers for devices such as hand-held printers are known to be capable of charging the batteries of a number of such devices simultaneously. One known battery charger has two rates of charging, a high charge rate and a trickle charge rate. A functioning battery is charged by this charger on a high charge rate until the unit senses a battery voltage of a predetermined end point level. As soon as the battery voltage reaches the predetermined end point level, the charger determines that the battery is fully charged and switches from the high charge rate to the trickle charge rate. This known battery charger further includes a timer that is started when a battery is detected. If the timer reaches a predetermined value before the battery voltage reaches the end point level, the charger switches to the trickle charge rate and flashes a red LED indicating a possible problem with the battery. The method used by this known charger for determining whether a battery is fully charged has been found to be unreliable. Further, the overcharge protection provided by the timer of this charger often results in batteries that are only 50% charged when the charger switches from the high charge rate to the trickle charge rate.